Electric snap-switch mechanism



I s l l w.A c. srEvENs E'r AL ELECTRIC SNAP SWITCH MECHANISM Filed sept. 29, 192e liiiiflHLllNL/ l snap Patented Dec. 9, 1930 l Unirse STATES PATENT OFFICE WILLIAM C. STEVENS AND GEORGE J. MEUER, OE MILWAUKEE, WISCONSIN, ASSIGN- ORS, BY MESNE ASSIGNMENTS, TO CUTLER-HAMMER, INC., A CORPORATION OF DELAWARE v ELEC'IERIC SNAP-SWITCH MECEAN ISM I Application I iled September 29, 1928'. Serial No. 309,299.

This invention relates to improvements in electric snap switchA mechanism, and more particularly to the combination of such switch mechanism with other elements to provide a novel form of free-tripping overload relay.

An object of the invention is to provide and-reliable construction for accomplishment of the novel results hereinafter set forth,

Another object is to provide snap switch mechanism having a plurality of sets of cov operating stationary and movable contacts,

together with improvedf manual and auto.l

matic operating and controlling means therefor.

Another and more specific object is to pro-` vide an overload relay 'or switch ha-ving means for insuring a snap make or break of the controlled circuit under all conditions, while insuring against completion of the controlled circuit under given overload conditions.

Other objects and advantages of the invention will hereinafter appear.

, AThe accompanying drawings illustrate an embodiment of the invention which will now be described, it being understood that various changes may be made in the details of without departing fromthescopeof the apv pend'ed claims.

In the drawings,

Figurel is a top plan-view of an overload switch constructed in accordance with our invention, with the switch housing removed.

Fig. 2 is a vertical sectional view on theline 2-2 of Fig. 1, with the switch housing yin position. Figs. 3 and 4 are vertical sectional views on the lines 3-3 and lr-4 of ,Fig. 1; .the

'switch housing beingshown` in position in Fig. 4 and partsof themechanism being broken away for purposes of illustration.

Fig. 5f diagrammatica-lly illustrates the s'witch'contacts, together with onetypeof circuit to be controlled thereby.

Fig. 6 diagrammatically' illustrates the various positions assumed -by 'the movable switchv mechanism of extremely' simple contacts incident to completion and interruptionof the controlled circuit; and

Fig. 7 is a detail view of a bimetallic electro-thermally responsive element which we may employ to render the switch responsive to overload conditions in the controlled circuit.

Referring to the drawing the numeral 10 designates a substantially rectangular insulating base, the corners of which are preferably rounded, as shown. Base 10 is pro? vided with a flat upper surface 1'1 extending throughout the major portion of its area, andl the same is also provided with a slightly raised portion 12 having a lat upper surface 13.

Resting upon the surface 13 is a U-shape-d I frame member comprising a connecting portion 14 and integral upwardly extending parallel arms 15 and 16, said portion 14 having suitable tapped openings into which screws 17 and 18 are adapted to take to secure .the frame member in'position.

The upper ends of the arms 15 and 1 6 of the frame member are preferably provided 'with slitted extensions 15L and 16, krespectively, of reduced width.v Theframe is also f provided-with a top plate 19'havin'g perforations through which the extensions 15a and construction 'and arrangement of the parts 16a are adapted to extend the ends of Said 'studs 20, each concentric pair of studs (Fig.-

3) being adapted to cooperate with the open of U-shaped cont-act carriers 22 and 23.

The contact carriers 2 2 and 23 are respectively provided with integral lugs or extenbearings 2l at the ends ofthe arms of a pair sions 22a and 23,'due to the iden-tical con# ,struction .of said carriers. However, as will appear, the lug 23a may be omitted if desired. The movable contactslof the switch may comand 25, preferably of copper, and each roller is preferably provided with a central rectangular perforation (not shown).

Each pairof rollers 4is carried by and non- `prise pairs of conducting disks or rollers 24 rotatably secured to the reduced rectangular ends of a cylindrical bar or shaft 26, preferably of brass, by riveting the shaft ends against the outer surface of the respective rollers, as indicated at 26a. The shafts 26, on the other hand, are rotatable within bearings formed by the semicrcularly bent lugs 27 and 28, on metal plates 29, and the enlarged outer ends 30 of substantially T- shaped insulating pieces or plates, as best shown at the left-hand side of Fig. 2.

The shanks 31 of the T-shaped insulating pieces extend inwardly through suitable openings in the free ends of the contact carriers 22 and 23; perforated disks or plates 32 of fiber or other insulating material being interposed between the free ends of said carriers and the metal plates 29. The shanks 31 of the T-shaped members are also perforated to respectively receive the hooked ends 33 and 34-of a coiled tension spring 35.

As will be apparent, the spring 35 acts to hold the assembled shafts and roller contacts 24 and 25 in position on their respective carriers 22 and 23, and the same further acts to hold said carriers upon their pivots 20. Moreover, said spring 35, upon bodily distortion or movement thereof inherently biases said carriers to swing jointly to one side or the other of their pivots 20, whereas movement of said carriers upwardly is limited by means of the top plate 19 of the switch frame and movement thereof downwardly is limited by the connecting portion 14 of the frame.

As aforestated, upon bodily distortion or displacement of the spring 35 from one side to the other of the pivots 20 the carriers will follow the spring jointly with a snap action. Accordingly we have provided actuating means which comprises a sheet metal stripor blank 36 having a perforation 37 through which said spring 35 is adapted to extend, said perforation preferably being circular and of somewhat larger diameter than the external diameter of the spring coil.

Top plate 19 of the switch frame and connecting portion 14 of the latter are provided with vertically alined perfo-rations 38 and 39, respectively, which serve as guides for the strip 36. The lower end 40 of strip 36 extends into a well or recess 41 in the base 10, and said strip is provided with an integral offset projection or lug 42 to limit the upward movement thereof. Said lower end 40 of the strip is of reduced width to p rovide shoulders 43 and 44 which are engaged by the upper end of a relatively heavy coiled spring 45 seated within the well 41. Downward movement of the strip 36 is limited preferably by engagement of the end 40 thereof with the bottom 46 of the well 41.

The strip is provided at the upper end thereof with an operating button 47 preferably of insulating material molded thereon.

The spring 45 is normally under sufficient compression to cause the strip 36 to return to its upper extreme position, as illustrated in Figs. 1 to 4. In other words,- the energy normally stored in spring 45 is sufiicient to overcome the resistance of coiled spring 35 to movement from a point below to a point above the plane of the pivots 20, and hence the contacts 24 and 25 will normally tend to assume the respective positions thereof illustrated in Figs. 1 to 5 and the first diagram of Fig. 6, wherein the contacts 24 are out of engagement with their cooperating stationary contacts 242L and 24", and contacts 25 are in engagement with their cooperating stationary contacts 25a and 25".

lrVhen the button 47 is pressed downwardly against the action of biasing spring 45 the medial portion of the coiled tension spring 35 is carried by the strip 36 to a point below the plane of the pivots 20, whereupon the carriers 22 and 23 and their associated cony tacts 24 and 25 are moved jointly, and with a snap action, from their respective cxtreme positions as shown in Fig. 2 to their opposite extreme positions. Such movement will cause engagement of contacts 24 with their cooperating stationary contacts 24fl and 24b and disengagement of contacts 25 from their contacts 25 and 25", as illustrated in the second diagram of Fig. '6.

`When push button 47 is released spring 45 acts to return the strip 36 to the position illustrated in Fig. 2, thus carrying the midportion of coiled spring 35 above the plane of pivot-s 20. 'This tends to cause snap movement of carriers 22 and 23 to their upper extreme positions (Fig. 2). However, we have provided means for holding the carrier 22 in its lower position under such conditions, so that the contacts 24 will be held in engagement with their cooperating stationary contacts 24n and 24 while contacts 25 are permitted to more into bridging engagement with their cooperating stationary contacts 25'L and 25" under the biasing action of springs 35 and 45, as illustrated in the third diagram of Fig. 6.

Said holding means for the carrier 22 may comprise a latch 48 pivoted at 49 to a supporting bracket 50, which bracket is in turn secured to basel() in any suitable manner, as by means of screws 51, one of which is shown in dotted lines in Fig. 2. Latch 48 is preferably slightly projected from or odset with respect to an integral downwardly extendmg portion 52 which may engage the walls of a recess 53 in base 10 to limit the clockwise and counterclockwise movement of the latch.

Latch 48 is also preferably provided with an angularly extending arm adjacent to the pivot 49, and attached to the outer end of said arm and to the horizont-al portion 55 .if bracket 50 is a relatively light coiled tension a bimetallic electro-thermally responsive ele- .50 by means of ment 59, the reexed upper end portions of which are united for ]oint movement by means of an insulated metallic clip 59". A

lock nut 60 is preferably provided for insuring maintenance of screw 58 in its ad- .justed position.

, Extending at an angle from the upper end of arm 57 isan arm 61 which is located in the path of a push button 62 to provide foi` manual release of the latch. Push button 62 maybe supported by a plate spring 63 riveted or otherwise secured-t0 the switch cover or housing 64, as indicated at 65. u

The bimetallic element 59 is preferably of the grid type, as shown in detail in Fig. 7; one end 66 of said element being riveted or otherwise permanently secured to the terminal plate 67 (Fig. 1) and the other end 68 thereof being likewise secured to a bus or conductor 69 leading to the stationary contact 24". c

The slit lower ends or reiexed portions 59" of the element 59 are secured against relative movement with respect to each other and to the lower vertical portion 70 of bracket a metal plate 71, suitable mica or other insulating plates 72 being arranged on opposite sides of said element, and the latter being provided with relatively large perforations 7 3 to eflectually separate or 1nsulate the same from the securing rivets 74 or the like.

As best shown in Figs. 1 and 5 the stationary contacts 24" and 25" are permanently electrically connected as by means conductor 75, and stationary contact 25a is electrically connected to the terminal plate`76 by means of bus or conductor 7-7.

Two or more angle brackets 78 are preferably secured to base 10 by means of screws 79 (Fig. 2) ,the upright portions of said brackets being provided with tapped openings to 'receive securing screws 80 'which extend through the lower skirt portion of housing 64 and its insulating lining 81. A

The l stationary contacts 24", '24" and 25, 25" preferably comprise silver buttons or points which are riveted or otherwise secured to resilient conducting. standards of like shapeiand size. It will be noted, however, that the standards carrying contacts 24", 24" are secured to the surface 11 of base 10 to cooperate with contact rollers 24 when carrier 22 is in its lower position, whereas the standards carrying contacts 25, 25" are secured to raised portions 82 and 83 of the base 10 to provide for cooperation of contactrollers' 25 of the bus or:

with said contacts 25", 25" when carrier 23 is in its upper extreme position. y

In Fig. 5 we have illustrated diagrammatically an adaptatlon of our invention to the control of a motor clrcuit, and the operation of the device will now be described-with particular reference to the diagrams of Figs.

5 and 6.

Thus in Fig. 5 the reference character M vdesignates a motor to be supplied with current froma suitable source, indicated by lines L1, L2. In the normal position of the switch the stationary contacts 25a, 25" are bridged by contact rollers 25 andtheir conducting shaft 26. .However, the motor circuit is not completed due to normal disengagement of contact rollers 24 from the stationary contacts 24", 24". lThis normal relative position of the switch elements is best shown in Fig. 2 and in the rst diagram of Fig. 6.

Moreover, upon depression of .push button 47 the carriers 22 and 23 move jointly and mal position under the action of thebiasing' springs 45 and 35, to cause re-engagement of contact rollers 25 with the stationary contacts 25a, 25".

This relation of the switch elements is illustrated in the third diagramof Fig.. 6. The motor circuit as thus completed may be traced (Fig. 5) from line L1 to'terminal plate 76,

bus 77, stationary contact 25a, to and through the brldglng'member represented by contact f rollers 25 and their conducting shaft 26, stationary contact 25", bus 75, stationary contact 24",.toand through the bridging member represented by contact rollers 24 and their conducting shaft 26, stationary contact 24, bus 69, to and through the grid type bimetallic electro-thermally responsive element 59 to terminal plateI 67, and thence through motor Muto line L2. l

l Under normal current/conditions incident to starting and running of motor M the switch elements will remain in the relative positions last described for maintaining the motor circuit connections. However, the bimetallic element 59 is so calibrated and arranged that upon predetermined overload conditions in the motor circuit the additional heating thereof due to the excessive cur.ent will cause the reflexed upper end portions to warp or bend jointly in a counter-clockwise direction (Fig. 2), and engagement of the clip 59a thereof with the screw 60 will result in corresponding movement of the latch 48 to effect release of lug 22'3L of carrier 22, whereupon the latter will move to its upper extreme position under the aforementioned bias of springs 45 and 35, with consequent disengagement of contact rollers 24 from the stationary contact-s 24a, 24h for interrupting the motor circuit.

It will be noted that when the electrothermally responsive clement 59 acts under overload conditions to cause interruption of the motor circuit it is not possible to immodiatcly complete the motor circuit by repetition ofl the aforementioned cycle of operation including depression and release of push button 47, inasmuch as the element 59 Will act to hold the latch 48 out of the path of lug 22n of carrier 422 for a period depending upon the degree of the overload and upon the adjustment of the screw 60.

After the circuit has been interrupted automatically in the manner just described, the element 59 gradually cools and returns to its normal position, thereby permitting latch 48 to return to its normal operative position under the bias of spring 56.

Assuming completion of the motor circuit connections in the manner aforedescribed, obviously the switch parts may be caused to lreturn at will to their normal circuit interrupting positions by momentarily depressing the push button 62, thereby tripping the latch 48.

lVhile we have illustrated in Fig. 5 the control of a motorto be started by throwing the same directly across the line, it will be understood that means for including suitable resistance in the motor circuit at starting may be employed if desired.

I/Vhat we claim as new and desire to secure by Letters Patent is:

l. In a snap make and break switch. the combination with a plurality of pivoted contactors, of a common spring connection between said contactors for normally biasing the same jointly to one extreme position or the other, means utilizing said biasingconnection for effecting movement ofi-said contactors jointly to opposite extreme' positions selectively and means biasing said last mentioned means to normally effect movement of said contactors jointly to one of said extreme positions.

2. In a snap make and break switch. the combination with a plurality of pivoted contactors, of ya common spring connection between said contactors for normally biasing the same jointly to one eXtreme position or the other, means utilizing said biasing conneet-ion for effecting movement of said contactors jointly to opposite extreme positions selectively, means biasing said last mentioned means to normally effect movement of said contactors jointly to one of said extreme positions, and means for latching one of said contactors in the opposite extreme position against the action of said biasing means.

3. In a snap make and break switch, the combination with a pair of separately pivoted contactors, of a -tension spring having the ends thereof respectively connected to said contactors eccentrically of the pivot points whereby said contactors are biased to one or the other of their extreme positions, means for distorting said spring to effect movement of said contactors jointly to said opposite extreme positions selectively, and means for biasing said last mentioned means in a given direction whereby said contactors normally tend to assume but one of said extreme positions.

4. In a snap make and break switch, the combination with a pair of separately pivoted contactors, of' a tension spring having,r the ends thereof respectively connected to said contactors eccentrically of the pivot points whereby said contactors are biased to one or the other of their extreme positions, means for distorting said spring to effect movement of said contactors jointly to said opposite extreme positions selectively, means for biasing said last mentioned means in a given direction whereby said contactors normally tend to assume but one of said extreme positions, a latch operable automatically for holding one of said contactors in its opposite extreme position against the action of said biasing means, and means operable automatically under given conditions for effecting releasing operation of said latch.

-5. In a snap make and break switch, the combination with ,a air of separately pivoted contactors, of a tension spring having the ends thereof respectively connected to said contactors eccentrically of the pivot points whereby said contactors are biased jointly and individually to one or the other of their extreme positions, means for distorting said spring to effect movement of said contactors jointly to said opposite extreme positions selectively, means for biasing said last mentioned means in a given direction whereby said contactors normally tend to assume but one of said extreme positions, a latch operable automatically for holding one of said contactors in its opposite extreme position against the action of said biasing .means, and electro-thermally responsive means operable automatically under given conditions for effecting releasing operation of said latch.

6. In a switching device, the combination with a plurality of sets of stationary and movable contacts, of snap operating means providing for closure of one of said sets of contacts and opening of another of said sets of contacts simultaneously, means biasing said operating means to cause disengagement of said first mentioned set of contacts and engagement of said4 second mentioned set of contacts,means for holding in said first mentioned set of contacts while permitting said 5" second mentioned set of contacts to close under such bias, and releasing means for said holding in means.

7. In a switching device, the combination with a plurality of sets of stationary and movloable contacts, of snap operating Ameans providing for' closure of one of said sets of contacts and opening of another of said sets of contacts simultaneously, means biasing said operating means to cause disengagement of said first mentioned set ot' contacts and engagement of said second mentioned set of contacts, means for holding in said iirst mentioned setof contacts while permitting saidI second mentioned set of contacts' to. close under such bias, and thermally responsive releasing means for said holding in means.

8. In a free tripping overload switch, the combination with a plurality of sets of stationary and'movable contacts, of snap operating means providing for closure of one of said sets of contacts and opening of another of said lsets of contacts simultaneously, means biasing said operating means tocause disengagement of said 4first mentioned set of contacts and engagement of said second mentioned set of contacts, automatically operable latching means for holding in said first mentioned set of contacts while permitting said second mentioned set of contacts to close under such bias, and electrosthermally responsive meansl in circuit with-each set of contacts for render- -ing said latching means ine'ective under predetermined conditions.

9. In a free tripping overload switch, the

40 combination with a pair of oscillatable contact carriers, of a frame to which said carriers are separately pivoted', a'spring having its opposite ends connected to the free endsvof said carriers respectively whereby the latter .45 are normally biased vjointly to one or the other of their eXtreme positions', means for distorting said spring to reverse the position of said carriers jointly with a snap action, means for biasing said distorting means in a given direction whereby said carriers normally tend to jointly assume one of their extreme positions, means operableautomatically for latching one of said carriers in its opposite extreme position against the action 55. of said biasing means, movable contacts on said carriers, and stationary Icontacts adapted to'be bridged by said movable contacts, certain of said stationary contacts being bridged by their `cooperating movable contact onlydwhen the latter is in its normally 4assumed position and the other of said stationary contacts being ,bridged only when their cooperating movable contact is in its latched position. v 10. Insnap switch mechanism, the combination with a plurality of stationary conifoscillatable contactors adapted to cooperate with'said sets of stationary contacts, snap operating means including means for biasing said-contactors jointly to one extreme position or the other, spring means to act upon said operating means for biasing said contactors jointly toward one of-their extreme positions, and restraining means to act upon one of said contactors for preventing movement thereof under said .last mentioned bias- When another of said contactors is moved to its biased position'.

12. In snap switch mechanism, the combi-v nation with two sets of stationary contacts arranged in different horizontal planes, of a pair of vertically oscillatable-bridging vcontactors adapted to cooperate with said sets of stationary contacts respectively, a reciprocating actuator for effecting snap movement of said contactors jointly from. one extreme positionto the other, said contactors when moved jointly to opposite extreme positions being adapted to alternately engage their respective stationary contacts, and means for latching one of said contactors in engagement with its cooperating stationary contacts whereby the other of said contactors may be movedv individually by said actuator into engagement with its cooperating stationary contacts.

13. In snap switch mechanism, the combi- .nation with two sets of stationary contacts arranged in diii'erent horizontal planes,4 of a pair of vertically oscillatable bridging contactors adapted to cooperate with 'said sets of stationary contacts respectively, the pivots of said contactors being horizontally alined, a reciprocating actuator, spring means connected-to said actuator and to the free ends of said contactors respectively whereby said contactors may be moved jointly to opposite extreme positions with .a snap action, means for biasing said actuator to cause movement of said contactors jointly to their upper extreme positions respectively wherein one of said contactors engages its stationary contacts and the other contactor is out of engagement with its stationary contacts, said actuator upon movement thereof against said bias being adapted to simultaneously effect disengagement of saidiirs'tmentioned A of said contactors respectively whereby said contactors may be moved jointly to opposite extreme positions with a snap action, means for biasing said actuator to cause movement of said contactors jointly to their upper eX- treme positions respectively wherein one of said contactors engages its stationary contacts and the other contactor is out of engagement with its stationary contacts, said actuator upon movement thereof against said bias being adapted to simultaneously effect disengagement of said lirst mentioned contactor and engagement of said second mentioned contacter, an automatically operable latch for holding said second mentioned contactor in engagement while permitting reengagement of said first mentioned contacter under the influence of said actuator, and a bimetallic electro-thermally responsive element to be connected in circuit in series with said stationary contacts and said contactors for effecting release of said latch under predetermined current conditions.

15. In an electric snap switch, the combination with a substantially rectangular openended metallic frame, of a pair of substantially U-shaped metallic carrier members pivoted in horizontal alinement with each other interiorly of said frame, the free ends of said carriers projecting outwardly through the respective open ends of said frame, means on said frame for limiting the oscillating movements of said carriers in opposite directions respectively, bridging roller contacts rotatably supported by the respective carriers but insulated therefrom, .a single coiled tension spring interposed between the free ends of said carriers and normally biasing the same for movement jointly to their upper or lower extreme. positions,'a rcclprocating actuator for distorting said spring to cause such joint movement of said carriers, means biasing said actuator to its upper extreme position whereby said carriers are correspondingly biased toward their upper extreme positions, means for latching one of said carriers in its lower extreme position against the action of said last mentioned biasing means, and sets of contacts to be engaged by said roller contacts simultaneously when said carriers are in the rcspective positions thereof last mentioned.

16. In an electric snap switch, the combination with a substantially rectangular openended metallic frame, of a pair of substantially U-shaped metallic carrier members pivoted in horizontal alinement with each other interiorly of said frame, the free ends of said carriers projecting outwardly through the respective open ends of said frame, means on said frame for limiting the oscillating movements of said carriers in opposite directions respectively, bridging roller contacts rotatably supported by the respective carriers but insulated therefrom, a single coiled tension spring interposed between the free ends of said carriers and normally .biasing the same for movement. jointly to their upper or lower extreme positions, a reciprocating actuator for distorting said spring to cause such joint movement of said carriers, means biasing said actuator to its upper extreme position whereby said `carriers are correspondingly biased toward their upper extreme positions, means for latching one of said carriers in its lower extreme position against the action of said last mentioned biasing means, sets of contacts to be engaged by said roller contacts simultaneously when said carriers are in the respective positions thereof last mentioned, and manually operable releasing means for said latch.

17. In an electric snap switch, the combination with a substantially rectangular openended metallic frame, of a pair of substantially U-shaped metallic carrier members pivoted in horizontal alinement with each other interiorly of said frame, thefree ends of said carriers projecting outwardly through the respective open ends of said frame, means on said frame for limiting the oscillating movements of said carriers in opposite directions respectively, bridging roller` contacts rotatably supported by the respective carriers but insulated therefrom, a single coiled tension spring interposed between the free ends of said carriers lthereof last mentioned, and alternative mauually operable and automatically operable releasing means for said latch.

18. In an electric snap switch, the combination with a substantially rectangular openended metallic fra-me, of a pair of substantially U-shaped metallic carrier members pivoted in `horizontal alinement with each other interiorly of said frame, the free ends of said carriers projecting outwardly through the respective open ends of said frame, means on said frame for limiting the oscillating'movements ofsaid carriers in opposite directions respectively, bridging roller contacts rotatably supported by the, respective carriers but insulated therefrom, a single coiled 4tension spring interposed between the free ends of said carriers and normally biasing the same for movement jointly to their upper or lower eXtreme positions, a reciprocating actuator for distort-ing said spring to cause such joint movement of said carriers, means biasing said actuator to its upper extreme position whereby said carriers are correspondingly biased toward their upper extreme positions, means for latching one of said carrie-rs in its lower extreme position against the action of said last mentioned biasing means, sets of contacts to be engaged by said roller contacts simultaneously when said carriers are in the respective positions thereof last mentioned and alternative manually operable and automatically operable releasing means for said latch, said automatically operable releasing means comprising a bimetallic electro-thermally responsive element to be subjected to the current conditions in the circuit controlled by said switch.

In witness whereof, we have'hereunto subscribed our names. WILLIAM C. STEYENS.

GEORGE J. MEUER. 

